OpenDNS is an American company providing Domain Name System (DNS) resolution services—with features such as phishing protection, optional content filtering, and DNS lookup in its DNS servers—and a cloud computing security product suite, Umbrella, designed to protect enterprise customers from malware, botnets, phishing, and targeted online attacks. The OpenDNS Global Network processes an estimated 100 billion DNS queries daily from 85 million users through 25 data centers worldwide. On August 27, 2015, Cisco acquired OpenDNS for million in an all-cash transaction, plus retention-based incentives for OpenDNS. OpenDNS's business services were renamed Cisco Umbrella; home products retained the OpenDNS name. Cisco said that it intended to continue development of OpenDNS with its other cloud-based security products, and that it would continue its existing services. Until June , OpenDNS provided an ad-supported service and a paid advertisement-free service. The services are based on software proprietary to the company. Products and services The name "OpenDNS" refers to the DNS concept that queries are accepted from any source. It is not related to open source software; the service is based on closed-source software. DNS OpenDNS offers DNS resolution as an alternative to using Internet service providers' DNS servers or locally installed DNS servers. OpenDNS has adopted and supports the DNSCurve secure protocol. OpenDNS provides the following recursive nameserver addresses for public use, mapped to the nearest operational server location by anycast routing. OpenDNS also provides the following recursive nameserver addresses as part of their FamilyShield parental controls that block pornography, proxy servers, and phishing sites. OpenDNS Sandbox is an RFC-compliant DNS service that does not provide any level of filtering. In July 2013 OpenDNS said that it handled over 50 billion DNS requests daily. In many cases OpenDNS provides only negligible performance gain, but may process queries more quickly than an ISP with slow DNS servers. DNS query results are sometimes cached by routers (e.g., local ISPs' queries may be cached by ISPs' home routers), the local operating system or applications, so differences in speed may be noticeable only with requests that are not stored in a local cache. DNS service for personal home use On May 13, 2007, OpenDNS launched a domain-blocking service to block web sites or non-web servers by categories, allowing control over the type of sites that may be accessed. The categories can be overridden through individually managed blacklists and whitelists. In 2008, OpenDNS changed from a closed list of